I declare this in knockout:
self.quizAnswer = ko.observableArray([{val: ko.observable()}]);
I can push the value there:
self.quizAnswer.push({ val: ko.observable('new') });
But tell me please how to easily read/rewrite the value like:
self.quizAnswer()[#position#].val = "new value";
I tried almost everything, but I dont know.
Thank you very much!!!
Because observable is function, you should invoke it without parameter to read its value:
self.quizAnswer()[0].val();
or with parameter to set new value:
self.quizAnswer()[0].val("new value");
Another option is to use knockout-es5 plugin. If you use this plugin you can invoke something like this:
ko.track(self.quizAnswer()[0]);
and after that you can access all observable of "tracked" objects like regular fields:
self.quizAnswer()[0].val = "new value"
Related
Newbie Alert! I feel silly asking this question but I need someone to teach me the correct syntax.
I have code that looks like this:
let thing: INewThing;
thing.personId = another.personId;
thing.address = another.work.address;
thing.greades = another.subjectInfo.grades;
thing.isCurrent = another.student.isCurrent;
I know it can be written cleaner. I want to use a lamda expression, something like this:
let thing: INewThing => {
personId = another.personId,
address = another.work.address,
grades = another.subjectInfo.grades,
isCurrent = another.student.isCurrent
} as IThingUpdate;
I have looked and looked for an example. I have yet to find one that works for me. It's just syntax but no matter what I try it doesn't work.
You're just looking to create a new object, which is a pretty different thing from a "lambda" (function). Just declare the object. You don't need a function.
const thing = {
personId: another.personId,
address: another.work.address,
// use the correct spelling below - no 'greades'
grades: another.subjectInfo.grades,
isCurrent: another.student.isCurrent,
};
If the another is typed properly, that should be sufficient.
If the another object had more properties using the same path, another option would be to destructure those properties out, then declare the object with shorthand, eg:
const originalObj = { prop: 'val', nested: { foo: 'foo', bar: 'bar', unwanted: 'unwanted' } };
const { foo, bar } = originalObj.nested;
const thing = { foo, bar };
Destructuring like this, without putting the values into differently-named properties, helps reduce typos - if a property starts out, for example, as someLongPropertyName, putting it into a standalone identifier someLongPropertyName and then constructing an object with shorthand syntax ensures that the new object also has the exact property name someLongPropertyName (and not, for example, someLongPRopertyName - which isn't that uncommon of a mistake when using the more traditional object declaration format).
But since all the paths in your another object are different, this approach wouldn't work well in this particular situation.
We are trying to build a component with a property variant that should only be set to "primary" or "secondary" (enum). Currently, we are just declaring the attribute as a String, but we were wondering if there is a better way for handling enums? For example, should we validate somehow that the current value is part of the enum? Should we throw an error if not?
I asked this question on Slack and the answers I got lean towards declaring the property as String and use hasChanged() to display a warning in the console if the property value is invalid.
Standard HTML elements accept any string as attribute values and don't throw exceptions, so web components should probably behave the same way.
This all sounds reasonable to me.
If you're using TypeScript I'd recommend just using strings. You can use export type MyEnum = 'primary' | 'secondary' to declare it and then use #property() fooBar: MyEnum to get build time checking. You can use #ts-check to do this in plain JS with #type MyEnum too.
This works well if the enums are for component options or that map to server-side enums that will get validated again.
However, if you want to validate user input into enums or loop through them a lot this is less good. As the JS runs it has no visibility of the type. You need an object dictionary, something like:
const MyEnum = Object.freeze({
primary: 'primary',
secondary: 'secondary'
});
// Enforce type in TS
const value: keyof MyEnum;
// Validate
const validated = MyEnum[input.toLower()];
// Loop
for(const enumVal of Object.keys(MyEnum)) ...
// Or Convert to a different value type
const MyEnum = Object.freeze({
primary: 1,
secondary: 2
});
These are somewhat idiosyncratic. Again, if you're using TypeScript it has an enum keyword that compiles to something like this and I'd use that rather than rolling your own. Strings are the better option unless you need to validate, loop or convert the values.
I am making use of withBatch API as:
int[] modifyCount = sql.withBatch(batchSize, updateQuery) { ps ->
keyValue.each { k,v ->
ps.addBatch(keyvalue:k, newvalue:v)
}
}
In closure, I set values for the placeholders in the updateQuery. It works fine.
Suppose updateQuery has already all the fields defined and hence code inside closure above is not actually needed now.
What change is needed for that?
there is no reason to use withBatch if updateQuery contains all values.
just use
sql.execute( updateQuery )
doc: http://docs.groovy-lang.org/latest/html/api/groovy/sql/Sql.html#execute(java.lang.String)
I am completely new to Dialogflow and nodejs. I need to get the entity value from the argument to the function (agent) and apply if the condition on that. How can I achieve this?
I am trying below but every time I get else condition become true.
I have created an entity named about_member.
function about_member_handeller(agent)
{
if(agent.about_member=="Tarun")
{
agent.add('Yes Tarun');
}
else
{
agent.add("No tarun");
}
}
Please help.
In such cases, you may use console.log to help unleash your black box, like below:
function about_member_handeller(agent) {
console.log(JSON.stringify(agent, null, 2));
if(agent.about_member=="Tarun") {
agent.add('Yes Tarun');
}
else {
agent.add("No tarun");
}
}
JSON.stringfy() will serialize your json object into string and console.log will print the same on the stdOut. So once you run your code this will print the object structure for agent and after which you will know on how to access about_member. Because in the above code it's obvious that you are expecting about_member to be a string, but this code will let you know on the actual data in it and how to compare it.
To get the parameter you can use the following;
const valueOfParam = agent.parameters["parameterName"];
For arrays I know you can do something like this:
function() {
}.observes("array.#each")
What I did was convert the object into an array and observe the properties with a #each, but is there a better way to observe object all property changes without converting it into an array?
You can observe isDirty to see if any of the object's values have been modified since last save (if you are using Ember Data).
Alternatively you can pass a comma separated list of properties to observes. This might be long if you have a lot of properties on your object, but will work.
A third approach could be to override setUnknownProperty() and set a property, a 'dirty flag' (or perform any action you may want in there.
There's also an old SO post that gives the following answer:
App.WatchedObject = Ember.Object.extend({
firstProp: null,
secondProp: "bar",
init: function(){
this._super();
var self = this;
Ember.keys(this).forEach(function(key){
if(Ember.typeOf(self.get(key)) !== 'function'){
self.addObserver(key, function(){
console.log(self.get(key));
});
}
});
}
});
You could probably split this out into a Mixin to keep your code DRY.
probably you could create something like a blabbermouth mixin and override the set method to get notified of property changes:
App.BlabbermouthMixin = Ember.Mixin.create({
set: function(keyName, value) {
this.set('updatedProperty', keyName);
this._super(keyName, value);
}
});
and observe the updatedProperty property?
You can get a list of properties in an object and apply them to a new property:
attrs = Ember.keys(observedObject);
var c = Ember.computed(function() {
// Do stuff when something changes
})
Ember.defineProperty(target, propertyName, c.property.apply(c, attrs));
Here is a working jsbin. Creating an observer instead of a property should be possible using a similar approach.